This invention relates to laminated bus bars, and more particularly to the type of laminated bus bars in which small ceramic chip capacitors are secured between the bus bar conductors in order substantially to increase the capacitance of the bars.
Multi-layer laminated bus bars of the type described herein are customarily employed to supply power to the components of electrical circuits of almost any variety. Typically such bars are designed to have the highest possible capacitance. Prior to the introduction of thin, ceramic capacitors, it was customary to provide this desired capacitance by attaching bulk capacitors at selected points to the exterior of the bar, and in certain instances to laminate one or more of the capacitors into the ends of the bar. More recently, however, the preferred process has been to laminate between the adjacent conductors of the bar a plurality of spaced, wafer-thin ceramic capacitors, which typically have a thickness in the range of 7 to 10 mils, and opposed surface areas on the order of a fraction of a square inch. This not only makes the chip difficult to handle, but also tends to complicate the assembly of the bars.
Apart from the difficulties encountered in assemblying the chips in the bars, it heretofore has been the practice to secure the various capacitor chips to the confronting surfaces of the adjacent conductors by the use of an adhesive, which in some cases has been conductive, as suggested for example by U.S. Pat. No. 4,236,046 and No. 4,266,091, and in other cases nonconductive, as taught for example by U.S. Pat. No. 4,236,038. However, as pointed out in the pending patent application of Lee C. Moss et al., Ser. No. 131,523, which was filed Mar. 18, 1980, (now U.S. Pat. No. 4,346,257) and which is owned by the assignee of the instant application, the presence of adhesive between the outer, metalized surfaces of a capacitor and the adjacent conductors will tend to reduce the effectiveness of the capacitors in the associated bus bar. It is therefore desirable to minimize the amount of adhesive which is employed for this purpose, and consequently to increase the proportion of the metalized surfaces of each capacitor which will engage directly with the confronting surfaces of the adjacent conductors.
It is an object of this invention, therefore, substantially to eliminate the need for employing any adhesive between a ceramic capacitor chip and the confronting surfaces of adjacent conductors in laminated bus bars of the type described.
A more specific object of this invention is to provide a bus bar of the type described in which the ceramic chip capacitors are secured in oversized openings in the layer of insulation which separates adjacent conductors in the bar.
A still further object of this invention is to provide an improved manufacturing process which results in maximum utilization of the capacitance afforded by ceramic capacitor chips which are sandwiched between the confronting surfaces of adjacent conductors in laminated bus bars.
Other objects of the invention will be apparent hereinafter from the specification and from the recital of the appended claims, particularly when read in conjunction with the accompanying drawing.